Optoelectronic property enhancement of conjugated polymer in poly(9,9′-di-n-octylfluorenyl-2.7-diyl)/titania nanocomposites

Optoelectronic property enhancement of poly(9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO) by different weight ratios of TiO2 nanoparticles (NPs) is demonstrated. The solution blending method was used to prepare the PFO/TiO2 nanocomposite. The microstructure of the composites was determined using X-ray diffraction while absorption and fluorescence spectra were recorded using UV–Vis and photoluminescence spectrophotometer respectively. X-ray diffractograms confirmed the formation of PFO/TiO2 nanocomposites. The absorbance and fluorescence spectra of the PFO/TiO2 nanocomposite were proportionately enhanced with the content of TiO2 NPs. The recombination between electrons of TiO2 and holes of PFO, through the interface of PFO/TiO2 nanocomposites enhanced the luminescence properties. Besides, the energy gap, line width of phonon emission intensity and vibronic spacing decreased. The line width of the energy gap tails, the vibronic transition intensity and the S-factor increased resulting from higher aggregation of films as supported by field emission scanning electron microscope images. The observed turn on voltage of the indium tin oxide/(PFO/TiO2)/Al organic light emitting diode device displayed a decreasing trend, suggesting an improvement on the performance of the device as the TiO2 content was increased.

► No variation in structure of poly(9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO) and TiO2.
► The absorbance and fluorescence spectra of PFO were enhanced with TiO2 content.
► The increase of PFO intensity upon addition of TiO2 due to charge trapping effect.
► The inclusion of TiO2 in PFO enhanced the conformational disorder.
► Incorporation of TiO2 reduced the turn-on voltage of organic light emitting diode.